Picked up my 1Dx last week.
I guess one could say I was sorta of an eye-fi fan owning 5 of the 8gig ProX2. i just find then very handy to have in the wife's camera, S95, works good in the 5Dmklll, 7D and even GoPro but it's performance is iffy in the 1Dx. Since you have to use the adapter and even though I've stripped mine I think heat becomes a concern as it did in the 5DMKll leaving you to have to open the card door to reset the error...so the results is is does work somewhat...transfers okay but will not take a lot of information without going into error mode..
Looking forward to trying the Toshiba FlashAir..

I would not call it a fault. The 1DX is made to be used with two CF cards. Not a SD card with adapter to fit the memory slot.
Canon say in the manual it works with Compact Flash (Type I or II), UDMA compatible cards.

Sir_Loin wrote:
I wouldn't call Eye-Fi rubbish. It's a great, cheap solution for wireless file transfers. Admittedly the Eye-Fi card and CF adaptor isn't the best solution in the 1DX but it works great in my 1D4.

NickD wrote:
I would not call it a fault. The 1Dx is not designed to work with tthat rubbish. There is a dedicated WFT-E6 for that purpose

I love my EyeFi cards. They work amazingly well in my 1D Mark III and 1DsII with transferring photos immediately to my iPhone in my pocket. What a great system. So when the WFT-E6 can do that instead of ONLY working with Canon's WFT program, let me know.

Will Patterson wrote:
I love my EyeFi cards. They work amazingly well in my 1D Mark III and 1DsII with transferring photos immediately to my iPhone in my pocket. What a great system. So when the WFT-E6 can do that instead of ONLY working with Canon's WFT program, let me know.

Yup I agree...and what does that device cost..plus extra weight and bulk hanging off the camera..We'll see what Toshiba has to offer soon I'd say..

I would be more inclined to look at the eyefi if they made the things in bigger sizes (16 or 32 gig) and even better if the made a cf version.

My 7D only has 1 cf slot and I don't need or want to A, clog up my iPad with raw files and B, slow things down by sending huge raw files to the iPad that doesn't need them.

Much better to be able to keep the raw on the card and send a smaller mjpeg to the iPad. But if I tried that at the moment I will fill the card up with raw.
And let's face it it's a very expensive 8gig SD card if I'm going to keep the raw files on it.

Ian.Dobinson wrote:
I would be more inclined to look at the eyefi if they made the things in bigger sizes (16 or 32 gig) and even better if the made a cf version.

My 7D only has 1 cf slot and I don't need or want to A, clog up my iPad with raw files and B, slow things down by sending huge raw files to the iPad that doesn't need them.

Much better to be able to keep the raw on the card and send a smaller mjpeg to the iPad. But if I tried that at the moment I will fill the card up with raw.
And let's face it it's a very expensive 8gig SD card if I'm going to keep the raw files on it....Show more →

I set up my 1D Mark III where I have it write small JPEG's to the SD (EyeFi card) slot. Then I set it so that photo review is set to the SD card. Then using the EyeFi card program on my laptop before-hand, I set it up so that files are trigger to beam to my iPhone when I press the lock button on my camera. So I browse through pictures I just took, find some I like and hit the lock/protect button, that tells the EyeFi card to send them to my iphone and they're there within seconds. There's no way I'd have it set where ALL the files are sent to my phone automatically.

I also like my Eye-Fi card and they're great if you understand and use them within their limitations. I'm always shooting RAW to CF and use the the Eye-Fi in the 2nd card slot of my 5D3 to send low res JPEGs to either my iPad (for focus checking / client viewing) or iPhone (for quick preview sharing). I know wireless transfer of RAW files via Eye-Fi card would be nothing but frustrating due to the speed and this the reason I bought the 4GB Connect X2 vs the 8GB Pro X2.

It's a great solution for me as it removes any need to shoot tethered to a laptop (no cable and less to pack/haul) and is cost effective compared to the Canon WiFi units which are extremely overpriced and bulky.

Following on from my previous post, it seems I use my Eye-Fi card like the majority of others here. On my 1D4 I set my CF card for RAW and my Eye-Fi for small JPG and transfer those immediately to my iPad for instant review. It's quick enough for me and I know immediately which images are worthy of keeping and those that are not. I think the £50 I paid for the 8gb Pro X2 was a bit of a bargain!

gpchase wrote:
I'd surmise individuals that express negative views of the card have never used one...

No but you have to be fair. Everyone in this thread saying that they like the eye-fi SD card. They use it in bodies that support and are made for SD cards. You like to use it in a body that only takes CF cards and not support SD

Will Patterson wrote:
I set up my 1D Mark III where I have it write small JPEG's to the SD (EyeFi card) slot. Then I set it so that photo review is set to the SD card. Then using the EyeFi card program on my laptop before-hand, I set it up so that files are trigger to beam to my iPhone when I press the lock button on my camera. So I browse through pictures I just took, find some I like and hit the lock/protect button, that tells the EyeFi card to send them to my iphone and they're there within seconds. There's no way I'd have it set where ALL the files are sent to my phone automatically....Show more →

Will , that's fine and if Iused my mk2n more than my 7D that's the way I would use it also. But as I said I have a 1 slot 7D so I can't use it like that.
I know cf is becoming a rare breed now but I think eyefi (or the other one that has come out since) would sell more if they did a cf version and/or a bigger 16 or 32gig version.

From what I've seen the eyefi and iPad are a great combo , but slowing things down transferring large raw files OR filling the card up with raw that you don't want to transfer is not the best use of the eyefi.

Maybe I need to revisit a pocket backup device that takes SD cards . Then I could dump the raw files onto that.

Lars Johnsson wrote:
No but you have to be fair. Everyone in this thread saying that they like the eye-fi SD card. They use it in bodies that support and are made for SD cards. You like to use it in a body that only takes CF cards and not support SD

Not quite correct..I used it in my 1DMKIV and it worked okay...not perfect but better than the 1Dx..Take note I'm not slamming the 1Dx for not supporting it..I just made a statement that it doesn't work well (as well) as other cameras..and they all reacted differently...even after altering the adapter case the 5Dmkll still would give an err if you pushed data to it too fast..I think the card would heat up in the adapter.

I'm talking about the old storage devices like the canon m80 and epson p (can't remember the number) etc.

I know you can still get them . But for me it would have to be cheap. It wouldn't need a screen or anything.

As for the above , using the eyefi in a 1series that takes both types of cards . I find that when I do use my mk2n I have a large(ish) cf card in 1 slot and shoot jpegs to the SD slot. Every time I have a small break I tak the SD card out and slip in a spare. Then I just stick the SD card in the iPads camera kit and let it upload .
Doesn't take long to do.
I guess if you have someone else holding the iPad and they are looking at the images as they upload then the eyefi is the thing to use.

Also
I've not looked at how the wtf's work (as I have no requirement for one at that price) but I'm sure I've read that you can send from the WTF to an iPad (or other) on an adhoc basis . I may be wrong though.